1. Field of the Invention
The subject invention relates generally to risers for stacking letter trays, and specifically to an adjustable support riser for stacking letter trays into alternate relative alignments.
2. The Prior Art
Stacking letter trays in an office environment are in widespread use. Typically such systems comprise at least two letter trays which are separated by at least two molded plastic risers, each of which having a lower end adapted to attach to a lower tray, and an upper end adapted to attach to a like-configured upper tray. Commercially available risers generally comprise an elongate body having a clothespin type clamping configuration at a lower end for affixing to the side wall of the lower tray. The riser furthermore comprises a socket at an upper end which is upwardly open. Letter trays to be used in the system provide a downwardly directed foot projection at each corner, whereby receivable into four risers spaced at the corners of the underlying tray.
Pursuant to the above state of the art risers, the upper tray fixedly attaches to the upper end of four support risers, which are in turn spaced along the sidewalls of the underlying tray, whereby the upper and lower trays are in parallel spaced apart co-alignment. A riser and tray system of the type described above is commercially available, for example such a system is sold by Rubbermaid Incorporated, Office Products Division, 1147 Akron Road, Wooster, Ohio 44691, under letter tray part no. 2131 and riser part no. 2132.
While the above letter tray and riser system works well, and has been generally well accepted in the trade, several shortcomings prevent the system from achieving the ideal objectives of the end user. First, the clothespin type attachment of the lower end of the riser to the upper side wall edge of the lower tray is subject to breakage because of the fragile plastic material, and because lateral stress introduced into the stacking tray configuration places stress into the clamping clothespin fingers of the lower end of the riser. Because both fingers of the clamping end are rather elongate, and narrow in width dimension, it is not uncommon for breakage to occur at this point of the riser.
Secondly, a shortcoming in conventional risers exists in the fact that the attachment between the upper end of the riser and the upper letter tray is fixed, and that a longitudinal realignment of the upper tray with regard to the lower tray cannot be effectuated. Therefore, a staggered tray stacking configuration is not achievable by means of adjusting the upper tray relative to the lower tray. The utility of existing riser and letter tray systems is therefore limited.